Terror of the Night
by Kamiko Kiyo
Summary: "Look, is it nightmares? Kids have those, right?" he asked uncertainly. Frisk just shook their head. If nightmares weren't plaguing the human child then why else did they keep coming to Sans in the middle of the night? One way or another, this needed to stop. Underfell AU. Oneshot.


Sans had never been so happy in his life. Hot dogs littered the ground like gravel and pillows were everywhere, just waiting for him to take a nap on in the warm dog bed that spread out for miles. No enemies around for him to keep his guard up against and every time he made a joke, a hearty round of laughter filled the air from the flying sock birds. Even Papyrus was there and laughed, telling him that there was nothing wrong with being a lazy bones and that they should go to Grillby's sometime which was never more than a few feet away whenever the thought to go occurred to Sans.

"Damn," he said, picking up a hot dog as his stomach growled hungrily for it. "The only thing this place is missing is…" He trailed as a shadow fell over him and he turned around. His jaw dropped and his eyes turned into little hearts before he grinned in pure euphoria.

"It _is_ real…" he whispered, his voice cracking. He wasn't crying, but the water flowing from his eye sockets made him kind of want to as he sniffled, "So beautiful," wiping his face with his sleeve.

Before him was a giant, golden bottle that he knew, deep in his non-existent monster heart, held a never-ending supply of the perfect flavored mustard that was just tangy enough without being too spicy. He couldn't help himself and blindly ran to it, giving it an eager squeeze to make mustard rain from the skies.

The pliant plastic bent under the pressure and he waited in anticipation, but when he opened his eyes the ground and sky was still very lacking in the yellow substance. Blinking, he tried again, squeezing the bottle harder. When nothing happened, he grew panicked and hugged his arms around it tighter, shaking his head in denial.

"N-No! NO! It can't be! Come on. Don't do this to me!" He constricted around it further. He just needed a little taste. One drop of the perfect mustard! "So. Close!"

When he squeezed with all his might, crushing his bones against the squishy bottle's exterior, he was rewarded with a small whine from the bottle as it groaned before weakly smacking at his face.

Smacking at his face?

Sans blinked and opened his eyes blearily, meeting the discomforted, slightly blue face of a little meatbag. His eye sockets widened.

"What the hell, kid!?" Sans let go of Frisk and shot up from his bed, pulling back the covers to make sure he was seeing correctly. Frisk lay there, panting and gasping for air gratefully but seemed otherwise unperturbed by having their lungs crushed by Sans. In hindsight, that mustard bottle was a little _too_ pliant. Rubbing their eyes, the kid tried to retrieve the covers to pull back over their cold form. Sans followed suit, scrubbing his hand over his eyes but was all too awake.

"When did you even get in here?" he asked intently with a sigh. He was a heavy sleeper, but he wasn't used to hearing the door opening or closing unless it was by him or Papyrus. And when it came to his brother, there was no way Sans would ever not notice him coming or going as he always announced his presence or departure.

Though reluctant to reply and, by extension, stay awake, Frisk shrugged and cuddled under the sheets with a soft smile and their shut eyes. They didn't really look that different from when they were awake to be honest since Frisk was always squinting.

Judging by their comfort in the bed, Sans had a feeling they'd creeped in fairly early in the night. He admitted, this was new, but not what he'd wanted when he'd told the kid to stop their nightly visits.

Frisk had more than enough room given their size and a very comfortable set up on the couch downstairs. Papyrus had seen to that. But for almost the past two weeks, without any warning, rhyme or reason whatsoever, Frisk had been coming into Sans' room and just… stared at him. Sans wasn't easy to scare, really, but waking up at an ungodly hour in the night while half asleep to look up and see a small child-shaped shadow looming over you was unnerving as all hell.

Frisk was a quiet kid. Sans had learned and gotten used to that. But this skulking into his room during the night was ridiculous. The first time they'd done it, when he'd awoken and the kid didn't say anything, just stood still as a statue over him, Sans' soul had nearly jumped out of his body. He'd also almost blasted Frisk with his magic, mistaking them for an enemy's surprise attack or some demonic creature from the darkest void.

He'd actually gone through with it by accident another time when Sans had gotten up for a glass of mustard in the middle of the night. On his way down the stairs Frisk had apparently been on their way up to go stare at Sans again because they'd been at the bottom of the steps, pausing when they saw him. However, Sans had only really noted the kid when he was at the landing, just before he descended, and at that particular moment lightning had struck outside.

The flash had illuminated the room for a brief second. This had been just enough time to allow him to notice the little figure in his path, their front shadowed by the light hitting their back. He hadn't thought or even mentally registered the disturbingly creepy air of the sight. All he did was feel the threat of something unknown in his home and, as he tended to do, he attacked and asked questions later.

The small cry Frisk had given out had horrified Sans and even awoken Papyrus. It was by luck of Sans having some potato chisps in the back of the fridge that had kept Frisk's HP from going down to zero.

Needless to say, his nights were getting stressful. Suddenly, his naps during the day were justified with the amount of sleep he was getting in his own home. He'd even tried to have Frisk sleep with Papyrus. He'd guessed that maybe they didn't want to be left alone downstairs on their own or that having someone with them would deter the kid from leaving to go to his room. Yet they always ended up coming to him no matter what, somehow without waking the taller skeleton either when they slipped out.

But they'd always just stared at him with that usual blank look on their face and the gaze boring holes into him would wake him up. This was the first time Frisk had actually just crawled into bed with him and the rest he'd gotten from not being woken prematurely did not feel as relieving as he thought it'd be.

"Kid, I've told you. Just stay with Papyrus," he grumbled. Even though it didn't work, Sans had hoped sleeping with his brother would get the kid into the habit of falling asleep on their own. Somehow. They couldn't wander in to disturb him if they slept the night through.

Frisk just shook their head while simultaneously cuddling into his jacket which he hadn't noticed they'd filched from the floor until now, hugging it like a comfort teddy.

Sans sighed. "Kid. This has got to stop. You need to tell me what's wrong or stop coming in here." Sans wasn't one to listen to other's woes, but if it got the kid to break this habit then he'd do it. It wasn't like they were very talkative in the first place and he more often complained that Frisk didn't say enough. Like when he was aiming a gaster blaster at their face, firing at them by accident.

When Frisk just snuggled into his jacket with a pleading pout, clearly not keen on answering Sans or stopping their behavior, the skeleton growled impatiently.

The really puzzling part was that Sans could see it wore on Frisk just as much. He didn't imagine standing barefoot in the darkness for however long it took Sans to wake up was easy. He'd seen there were light bags under the kid's eyes that were getting darker every day and the lack of sleep was much more destructive for the child than it was for Sans.

Just the other day, Frisk had been helping Papyrus in the kitchen, stirring the pasta while his brother had been making the tomato sauce. In his natural obliviousness and being blissfully preoccupied by cooking, Papyrus hadn't noticed that the kid's eyes were drooping and their stirring grew slower and slower in the warm, soothing, moist air of the kitchen. When Sans had walked in to see how dinner was coming, he'd just had enough time to use his magic to lift Frisk into the air before the kid had passed out head first into the boiling pot that was nearly twice their size.

In all the commotion, Papyrus had spilled the tomato sauce and afterwards Sans had wearily convinced them all to go to Grillby's instead. Then, while they'd been eating and Sans had pulled the classic loosening the salt shaker top prank on Frisk, the kid hadn't even reacted to or registered the pile of salt spilling onto their fries when they'd tipped it. Instead, they'd kept eating only to take a mouthful of salt when they'd stuffed a handful into their mouth mechanically. If they hadn't noticed the salt they'd probably have tried to eat the shaker top as well.

Sans had still laughed hysterically at the kid's disgusted face, watching as they tried to wipe the salt off of their tongue before washing their mouth out by chugging down some water. But the brief high of amusement faded very quickly and his continuous laughter and joking afterwards had all been a front. If he was honest, the kid was worrying him by being so out of it. As a result, he'd begun to grow anxious when Frisk wasn't around, wondering what else might happen to them when he wasn't there to keep watch.

Frisk's lack of attention and inability to stay awake was going to be the death of Sans if it wasn't Frisk's death first.

"Look, is it nightmares?" Sans guessed in response to Frisk's usual lack of verbal expression. "Kids have those, right?" he asked uncertainly. Sans' experience with kids didn't go beyond messing with them for his enjoyment and snarling at them to go away. Thus, dealing with Frisk was entirely a learning experience for him.

That gave the child a pause as Frisk averted their eyes thoughtfully. Now fully awake, though they didn't get up from comfortably lying on their side, they pressed his jacket to their face, looking hesitant and even a bit perplexed themselves. Sans did his impression of raising a brow, but waited with as much patience as he could muster. Surely there was a reason for this madness and once Frisk told him, he could take care of it and be done with it.

Frisk just shrugged, as knowledgeable as if Sans had just asked them to explain quantum physics. The monster scowled at their indefinite answer, gesturing for them to elaborate more. Frisk just shook their head.

Sans groaned, putting his head into his hand while he rested his elbow on a drawn up knee. If nightmares weren't plaguing the human child then why else did they keep coming to Sans in the middle of the night?

"Kid, _why_?" He verbalized his frustrations. "Night after night, you do this. _Why_?" he asked gruffly.

Frowning as they searched for an answer, the only response Frisk managed was giving Sans a sheepish, apologetic smile.

Sans looked at them out of the corner of his eye. He wasn't impressed.

"What am I gonna do with you, kid?" he asked himself rhetorically.

One way or another, this needed to stop.

…

"Wuh?" Sans was awoken by a light rattling and he glanced over at his door where it seemed to be coming from. He squinted as his sight adjusted and could just barely see the knob jiggling in the darkness. He'd locked it this time, expecting Frisk to just leave. They'd seemed intent not to wake him up when they'd stared at him in the night for the last week or so, but apparently that courtesy was no longer going to be given to Sans.

Not daring to give the clock a look, he rolled onto his stomach to go back to sleep only to be awoken by a soft knocking. It was gentle and shy, but still very insistent to get the attention of whoever was inside the room. That someone currently being Sans.

"Go to bed, kid." He ordered with a yawn. The knocking continued in intervals. _Knock, knock_. Then silence as they waited. _Knock, knock_. More silence. _Knock, knoc-_

"Kid. _Stop it_. I am done with this. Go back to bed, go sleep with Papyrus, go somewhere else I don't care about, just stop trying to come in here," he growled firmly. He rubbed at his eyes, waiting for the knocking to resume and considered how to handle Frisk, barring throwing the kid outside into the snow and locking that door too. Even in his sleep deprived state, he had enough foresight to know that he'd greatly regret that later if he followed through with it.

But the sound never came. Instead, after what had to be a solid three minutes, he heard quiet footsteps walking down the hall. Then, even farther off into the distance, he could hear the slight groan of the stairs as Frisk descended to the first level. He didn't even take a moment to sigh in relief and instead let the oblivion of sleep take him the next instant. This little episode was finally over and he could get a full night's sleep.

…

This little episode was not over. In fact, it was getting to be a bigger problem the longer it dragged on. Sans had woken up way earlier than what was natural for him, but he hadn't been able to fall back asleep and decided to head downstairs for some breakfast.

When he walked out into the hallway, running a hand over his face, something caught on his foot and he suddenly lost his center of gravity and tumbled forward towards the ground. He yelped in surprise and grunted as he slammed into the floor, sprawled out in front of his room, face first. With little sleep, the fatigue of the last few days building and his current hunger, Sans was in no mood to deal with any shit. He rose onto his knees and glanced back with a burning red eye to glare at whatever had tripped him with full intentions of giving it a good kick before blasting it to smithereens.

Yet his anger instantly evaporated, replaced by shock and then aggravation. "Damn it, kid." Frisk was curled up like a dog at the foot of his door with nothing more than a pillow and a blanket to cover them. They must have been just as exhausted as Sans, if not more so, if his tripping and falling right over them hadn't woken the human child up. He saw it fit that that be changed, not without a small bit of payback in mind, as he crawled towards the child with a sadistic gleam in his eye.

Sans was about to do the honors, ready to shake Frisk awake violently when he realized that they were shivering and their nose and cheeks were slightly red as if they'd just come in from being outside. Stolidly picking up a loose part of the blanket, Sans rubbed it between his fingers. It was thin as he could very easily feel the hard bone of his fingers meeting and grinding on each side of the flimsy fabric that offered little cushion.

It should have been no shock to him. They lived in a constantly cold climate and even if they always kept the heat on, the skeleton brothers didn't get as cold as a human did, so they didn't keep it quite as warm. Even if they'd kept it warmer for Frisk's sake (and they did so on occasion when the temperatures outside dropped much further) the floor was the coldest place to sleep. He knew from experience.

He'd thought the kid had gone back downstairs to go to bed, but apparently it had only been a trip to retrieve the barest necessaries to allow them to camp out in front of the locked door. Frisk would rather sleep outside of his room on the cold ground than sleep alone or even with Papyrus.

"What am I gonna do with you, kid?" He asked softly, the urge to wake Frisk no longer sitting well with him. If there was going to be a repeat of this later tonight, Frisk would need all the sleep they could get.

…

Frisk was nodding off in front of the TV keeping Sans' pet rock, Lump, company on the couch. Papyrus was out training with Undyne and Sans had left before they'd even woken up. In fact, they'd woken up on the couch instead of where they'd fallen asleep. They really hoped Papyrus had been the one to move them. No matter what they did, Sans wasn't happy about their night time excursions to his room, but they just couldn't help it.

To be fair, they'd never actually _asked_ Sans if they could come into his room or sleep in his bed. Sans had never said no nor had he said yes to them, so it made sense he'd be angry that they were invading his private quarters. Though, with all that was said (or not said) and done, Frisk was fairly certain they knew what the answer would be now if they did muster up the courage to request to sleep with Sans. He was nicer to Frisk than most monsters, but he was far from eager to fulfill to Frisk's every want and desire like Papyrus was despite the taller skeleton's attitude when Frisk did occasionally ask for something. But it wasn't as if Frisk had planned to harass and annoy Sans.

Every night Frisk promised themselves that they wouldn't do it. But then they'd fall asleep, wake up, oddly tired and drained, and then end up walking towards Sans' door like they were possessed. Even when they'd slept with Papyrus, once they woke up, they couldn't get back to sleep no matter how sleepy they were. The most Frisk had ever lasted was about two hours before going to see Sans.

At first, they hadn't wanted to wake him up and waited for him to wake up on his own. That was about as far as Frisk's plan ever got. From then on, they just played it by ear. All the while Frisk contemplated going back to sleep, but the debate continued indefinitely and Sans always managed to wake up before Frisk made a decision to rouse the skeleton or retreat. After a while, Sans had gotten fed up and sat Frisk down with a reproaching frown.

"Kid. Frisk." Using their name was reserved exclusively for when he was serious, so Frisk knew things were getting more severe. "You can't just sneak into my room and stand by my bed side all night. You need to sleep. I need to sleep. Uninterrupted," he'd added with a pointed look. "Promise me you'll stop," he told them bluntly.

With a guilty look, Frisk had nodded to Sans' satisfaction. But when the time came to follow through on it, Frisk found a loophole. After sitting on the couch for some time, thinking over what Sans had said, Frisk had made what seemed like a logical decision at one-thirty in the morning. Sans was upset that Frisk kept waking him up. Anyone would be upset. But if Frisk slipped into bed without waking him, then there was no reason for Sans to be mad, right?

"Head's up, kid."

Frisk blinked out of their reverie and twisted their head around in confusion a split second before something big and soft blinded them, burying them in fluffiness.

Sans chuckled as he watched the human flailing around in shock then fighting to find a way out of the blanket that the skeleton had just tossed on top of them. It was light but thick and swallowed the kid entirely, leaving nothing to see but a Frisk-shaped figure under the fabric as they struggled to tunnel out, only to succeed in twisting it further around them.

Again and again the small lump that was Frisk tried to crawl one way to freedom only to hit a dead end of blanket blocking their way. They would give a pause before going backwards and becoming even more tangled up each time. After a good minute or so of watching this and laughing his ass off, Sans gave one last bark of laughter before approaching with his arms raised as if Frisk could hurt him by moving too suddenly.

"Alright, alright, just hold still, kid. I'll getcha out." Frisk went still with a tired sigh from the exertion and after some experimental pulling and tugging of the cover (how the kid managed to get the blanket caught in the deepest cracks of the sofa in multiple places, Sans wasn't sure) Frisk's head popped out with a gasp. Their hair was messy and a little fuzz was stuck in it while the rest of their body remained snug but not quite as caught in the folds.

Sans snickered again. "What am I gonna do with you, kid?" he mumbled, shaking his head with a playful grin. For how tough and independent Frisk was, they could be surprisingly helpless at times. They'd traversed the perilous Underground with nothing but a sentient flower and a stick (which they never even used). They'd managed to befriend even the most cold, ruthless monsters, but couldn't manage to free themselves from being trapped in a comforter without his help.

"Comfy?" Sans asked with a lazy smirk, greatly amused by the sight before him as he sat beside Frisk on the couch. The child looked a burrito all twirled up as they were.

Frisk considered Sans' possibly rhetorical question, frowning and tepidly trying to free their arms. Sans saw their little elbows poking out as far as they could before becoming restricted by the cloth to no avail. It was admittedly kind of cute.

"Is it warm?" He asked instead, a little more seriously despite his light tone.

Putting their plans for escape on hold, Frisk snapped their head up at Sans quizzically then gave a slow nod.

"Good. Listen kid. Is there really not a reason that you keep trying to come into my room?" The only thing he knew was that Frisk wouldn't go to sleep unless Sans was nearby. And unfortunately being in the same house wasn't close enough for the kid.

"It's been hell on the both of us and I can see you're pretty determined. There has tibia reason," he insisted. He really wasn't even sure what Frisk was trying to do. He turned it over in his head every way he could, but Frisk's behavior was just an enigma to him and apparently to Frisk themselves too. Sans couldn't figure out what had caused this new development or the underlying need Frisk seemed to have for coming to him at night for the life of him. By nature, they were not a needy child in the least, making the situation even more unusual.

It appeared he wasn't the only one more than a little frustrated with the situation as Frisk let out a huff and pressed their nose into the neckline of the blanket cocoon around them. How could Frisk begin to explain their compulsion to seek out Sans when they woke so abruptly in the night? There just wasn't a reason. Frisk just couldn't sleep without going to Sans.

The child gave him an apologetic shrug as Sans closed his eyes briefly.

Of course it couldn't be that easy. "Then here's the deal. I'm not gonna lock the door on ya again," he told Frisk, causing them to whip their head up with an owlish look of disbelief.

"I'm serious," he reassured Frisk who appeared skeptical. "If you need me… and I mean really need me, you can come inside."

A bright smile slowly broke out on Frisk's face and they hopped towards him likely in an attempt to hug him. He stopped that quickly by putting his hand up.

"But…" Frisk's grin froze and slowly devolved into a look of bewilderment. "You're still not coming into my room to sleep. Maybe I wasn't clear enough with you other day, but here's the bottom line. You need to sleep on your own. Okay?"

Frisk sighed with an accepting nod.

Sans locking the door had been both saddening and relieving to Frisk. They understood that they'd pushed too far by climbing into bed with Sans and he didn't want to deal with Frisk anymore. It hurt even though Frisk had had it coming, but the internal struggle of what to do once they were inside Sans' room was eliminated at least. The night before when they'd been outside the idea of sleeping right where they stood had struck them and seemed like a good idea at the time. Apparently it was close enough for Frisk to fall asleep, but they wouldn't have to disturb Sans.

"And no more sleeping outside my room like… like last night." Sans' voice grew quiet and that familiar look of discomfort came over his face as he averted his gaze.

Frisk had a look of devastation before reading his face and realizing that Sans wasn't cutting them off completely. Tugging their arms out of their blanket mummification through sheer force of will, Frisk reached out to tug at Sans' jacket with a hopeful look on their face, leaning on their other arm since their lower half was still caught in the blanket. When the skeleton begrudgingly met their eyes, Frisk gently tugged again, prompting him to continue.

"Okay, okay! Here's the _whole_ deal," he relented. "I won't lock my door. No comin' inside unless Undyne is burning the house down with her baking or something _and_ … you can sleep outside my door," Sans said slowly as if every syllable pained him. "… So long as you use this blanket instead of that shitty one from the couch." He picked up the discarded fluffy black cover to emphasize his point.

Frisk nodded contentedly in agreement and for once Sans was dismayed at what a tolerant child they were.

"I don't want to hear any complaints about being on the floor," he added strictly even though he knew Frisk could end up sleeping on a bed of needles and wouldn't say a word. The kid's determination had gotten them through much worse. Hell, they'd befriended _Undyne_. He didn't know why he'd ever thought Frisk would give up on this, such a small, simple goal in comparison.

Frisk nodded again, but stopped as their attention was diverted to something on the floor. They picked up the neglected pet rock that had fallen to the ground in their struggle, dusting it off with a light petting before gently depositing it into Sans' hand.

"Hm? Keeping an eye on Lump, huh?" Sans said looking down at the stone lump he'd so creatively named. (1)

Frisk smiled in confirmation and pointed to the table where a bowl of sprinkles and chocolate chips sat. "And you fed him too?" Spoiled was more like it, letting him have sprinkles _and_ chocolate chips. With an easy grin, Sans patted and ruffled Frisk's already disheveled hair just a little harder than necessary, causing the human child to give a small whine and hold their head protectively when his jostling ceased and he pulled away.

"Good kid," he praised them. "How about we out-vote Papyrus on dinner again tonight and go to Grillby's?" he suggested, receiving eager consent in response as their grin turned conspiratory. He wondered how long it would take his brother to realize that, with the kid on his side out of the three of them, Sans would always win. That was, if Papyrus wasn't just letting Frisk choose by being the obvious tie-breaker.

Things were finally starting to look up.

…

Sans' eyes fluttered open when he heard two soft thuds. His first thought was that Frisk had decided sleeping outside his door wasn't good enough and they were trying to get him to let them in again. Back to square one.

But as he lay in bed, trying to psych himself up enough to deal with the child, he heard another thump, but another one didn't follow. Frowning, he laid back and listened, focusing his hearing on the outside of his door. When he did hear the occasional thuds they were irregular and different compared to someone purposefully knocking. It sounded more like something kept hitting the door by accident causing it to shake in its frame.

Eventually Sans' focus allowed him to hear something he hadn't noticed before.

A soft whimpering.

"Kid…?" He murmured as he threw the covers off and got up. The closer he got to the door the more clearly he could hear it. Soft sobbing and shaky breaths so muted that they would have easily gone beyond notice if one hadn't been listening for it.

There was another thud on the door before Sans opened it and looked down, squinting in the darkness to see Frisk curled into themselves under the blanket he'd given them as their legs kicked out sporadically. They were quivering and sobbing, but even now he could barely hear it as if Frisk, even while unconscious, was trying to keep as quiet as possible, holding it all in when they looked like they wanted to cry and wail like there was no tomorrow. The only thing more disturbing was that their eyes were open, wider than Sans had ever seen them while Frisk was awake or asleep, as they choked down their cries.

"Kid? Frisk! Wake up." Sans grabbed their arm and shook gently, but that only caused them to recoil violently like his hand was fire and the fear in their eyes to grow. Frisk then shot up, sitting to face Sans, but didn't seem any more aware or comprehensive as they trembled and cried quietly. Their tears noticeably dampened the front of their trademark purple and blue sweater.

Frisk didn't normally speak much, but when they did it was very clear, like they had carefully thought over every word and strung them together tediously. However, now the kid was spouting gibberish, no more coherent than a baby, but their tone was as panicked and fitful as their spastic movements. Frisk's head swung around and twitched constantly as if searching or even watching for something and when they did look at him it was more like they were looking through him.

"Kid, come on, this isn't humerus! It's me, Sans!" He tried to get some reaction out of them. Without thinking, he lit his eye up to chase away the darkness and reached out to hold the sides of their head to look at him. The moment he touched them, Frisk let out an ear-piercing shriek and swung their fisted arms out at Sans.

The skeleton shot back, dodging by an inch and growled in annoyance, frustration and concern all at once before he attempted to restrain them. All the while, he had to listen to Frisk's relentless screams and blabber like someone was killing them slowly and painfully or they witnessing something so horrific their mind couldn't handle it. However, the kid was strong and pinning them down was easier said than done especially with the way they would throw out or wrench their arms without any warning.

After a particular shove nearly knocked Sans into the wall, he understood that there was no way he'd be able to stop them physically. He wouldn't have worried about it so much if not for Frisk's sporadic, jerky movements. Sooner or later they'd hit something or worse, hurt themselves.

Just then Papyrus emerged from his room, his special attack in hand. "Sans! What's going on!?" He asked, looking around frantically, ready for battle as always.

"Papyrus!" Sans glanced at his brother just as he saw Frisk move out of the corner of his eye. The kid stood faster than their legs could support them and they stumbled backwards in their disoriented state. The wobbled unsteadily, stumbling back over the edge of the landing.

Sans' quick reflexes saved Frisk as his blazing hand shot out to grasp their soul which took on a crimson aura, holding them mere feet before they'd hit the ground. Despite floating in the air, Frisk's thrashing didn't stop and only got worse as their legs were now free to kick around.

"I don't know!" Sans' shouted a reply to his brother over the sound of Frisk's violent weeping and nonsensical prattle as he focused on keeping the child in the air. Frisk was too strong for even both of the skeletons to hold down and suspending Frisk like this would prevent them from hurting themselves as well.

"Did you do something to make the human act this way!?" Papyrus demanded.

"What!? No!" Sans shouted, insulted. "L-Look, I didn't _do_ anything!" he asserted. "I found them like this."

"Is it a sickness!? What's wrong with them!?"

"Hah! Sickness?" Sans scoffed, sweating as even Frisk's soul squirmed relentlessly. "No clue, but I'm sure sick of them acting like they're possessed!" Sans just wanted it to stop. He'd never complain about Frisk being quiet again. If this was the alternative, he'd take the mute little meatbag any day.

"This is no time for jokes!" Papyrus reprimanded him. "I'm fairly certain that the human screaming in distress like this is not a good thing to be happening!"

"The kid's having a nightmare or something!" Though he'd never seen a nightmare like this. People didn't sleep with their eyes open, at least Frisk didn't. Sans had seen them asleep plenty of times and even then, a nightmare shouldn't be lasting this long nor should it have prevented Sans from waking the kid. Frisk was probably screaming their throat out, but that, nor the sound of their own voice, was waking them.

Just as Sans worried that he might not be able to keep up his hold on the flailing child, Frisk's crying faded along with their struggling, growing quieter and stiller as the long, tense moments passed by.

The brothers watched with bated breath as the human went limp in the air and even the occasional kicks and jolts died down. They'd gone from deranged to listless in no time flat.

Frisk blinked languidly and lifted their head enough to look at the two, appearing lost as they glanced down to see no floor beneath their feet dangling in the air. Spotting their soul outside of their chest, they locked eyes with Sans, conveying their sluggish confusion and unease, but it was nothing compared the sheer terror the kid had exhibited before.

"You're awake," Sans sighed in relief deeply, turning his palm up and drawing Frisk closer with a flick of his middle and index finger until the child could safely stand on the second floor.

"Human! Are you alright!? What happened!?" Papyrus dropped down to his knees to fuss over Frisk. Even if Frisk would reply, they probably couldn't with their shredded throat which they held a hand to in a daze, coughing with a grimace.

Sans let out a heavy breath, collapsing down on the floor and placed his head in his hand as he leaned onto his knee for support. He didn't expect Frisk to give Papyrus a better answer to all this than the one they'd given Sans, so he quickly tuned them out, letting his eye go out and the usual white dot of light in his eye socket resurface.

This was far worse than he'd ever thought.

"What am I gonna do with you, kid?" he uttered under his breath, worn out and at the end of his wits.

Despite his hushed voice, Frisk turned their head towards him, knitting their eyebrows together when their eyes met before casting their gaze down to their feet. He understood.

Frisk was at just as much of a loss as him.

…

The next day, Papyrus stayed with Frisk, deeming that last night's incident was due to lack of nutrition, claiming that they were eating at Grillby's too much. He'd then declared that he'd take Frisk with him to Undyne's for their cooking session to make sure they had some "real food."

Sans would have balked at the thought of Frisk in the kitchen again, but reasoned it was okay if Undyne was around. Sure, the fish woman burnt her house down on multiple occasions, but she would be damned and probably use them for spear practice if anyone ever dared accuse her of letting her "little bestie" be hurt on her watch. They did always make it outside without a single burn when she tried baking. The same couldn't be said for their clothes, however.

Assured that Frisk would be okay, Sans had set out after breakfast, but not before having a talk with them. Last night they'd all been too exhausted to do anything rather than just go to sleep, though Sans had left the door wide open this time. When Sans had asked Frisk what had happened, the kid had been uneasy, but more open to trying to explain themselves than before.

There wasn't much to explain though. As far as Frisk knew, they'd gone to sleep and then woken up with a sore throat and Sans holding them in the air by their soul. The skeleton didn't push them to talk much more since it was obviously hard on them to swallow let alone speak.

They didn't remember a thing. Sans would've called them out as lying if he didn't know Frisk so well and could see the outright dumbfounded look they had when he reminded them that their face and shirt had been wet with tears. When they'd shyly asked Sans to recount what had happened, he had been frank with them. Normally he acted as such because he didn't give a damn about someone's feelings, but in Frisk's case, he told them every grueling detail because they deserved to know. Babying them and shrugging off the situation wouldn't help and Sans knew that they could take it. Besides, if they really wanted to know exactly what had happened while they'd been "asleep" it wouldn't take them long to get it out of Papyrus or figure it out for themselves.

The kid had grown solemn then, but nodded in that gravely accepting demeanor that had bothered Sans since they first met. Frisk was no ordinary child, but the action and mannerism on them was so very out of place. Even in their world most children were still kids. They were mischievous, hard-headed, rude little shits often way in over their head, but still juvenile. They didn't have the same kind of mature durability and resilience that Frisk did. But even then, Sans could see this situation was getting to them, wearing them down slowly just like their lack of sleep.

He'd decided that there was only one thing to do. The only person he could honestly feel safe enough to confide in with. It also helped that the same person had first-hand experience with Frisk and genuine care for them as well.

 _Knock, knock_. He waited for a reply, hoping she was around. They only ever saw each other by luck or making plans the next time. It wasn't like she ever came out of the Ruins so she'd only be at the door if she were waiting for him.

"Who's there?" came the smooth, terse reply.

"Ketchup."

"Ketchup who?"

"Ketchup with me and I'll tell ya," Sans grinned lazily as he turned to lean his back against the door, listening to the soft ensuing laugh from the other side.

 _Knock, knock._

"Who's there?" Sans asked.

"Nana."

"Nana who?"

"Nana your business," she replied, causing the both of them to laugh at the terrible jokes they both enjoyed that made others groan at the corniness. It was part of the reason they loved them.

"You haven't been by in a while," the old lady stated calmly once her demure giggles had died down. There was no bitterness in her tone, just a hint of curiosity about his absence.

"Heh. Yeah, I've been busy so I haven't had much time to relish in your company," Sans joked half-heartedly.

"And you want me to lend you an ear," the woman concluded, causing him to frown in surprise. Was he really that transparent?

"What makes say that?" he asked coyly nonetheless.

"You don't sound as enthusiastic about our meeting as you usually are," she stated. "Either the jokes aren't tickling your funny bone or you've got something you want to get off your chest."

"Huh. Well, I mustard the effort to come here after the night I had, so sure. Why not?" he said nonchalantly.

"Jokes suit you better than sarcasm," she retorted, but he knew that she was intrigued. "Tell me about your night," she ordered him in that oddly regal tone she sometimes used.

"Oh, it starts a lot earlier than just last night," he informed her with a humorless laugh.

"Then start from the beginning."

Sans relayed what had been going on the last two weeks, telling her about Frisk's staring contests with his back and then how they'd snuck in to sleep with him. He told her about how he'd tried to deal with it at first, how confounded the whole situation left him and how it was affecting Frisk as well. Even as he retold the events of last night, she was very quiet. It was hard to read the silence she was giving him, but Sans knew she cared for Frisk like her own child even if she tended to be dismissive and distant whenever the human came up in their conversations.

"I just don't know what to do with the kid." He'd indulged Frisk in the beginning. When they came up, he escorted them back to bed, gave Frisk some water, made them a snack and even stayed with Frisk on the couch until they fell asleep only to fall asleep himself in a rather uncomfortable position. Nothing truly worked. It only killed time during the night.

But what happened last night was something else entirely and Sans was clueless as to how he should handle it. He didn't know if he could even deal with it himself, let alone help Frisk.

"It may appear serious to you, but they _are_ still just a child," she finally spoke to him as if it made everything clear. This made Sans glare down the path since he couldn't fix it on her.

"Oh. So screaming their head off from a nightmare that they won't wake up from or remember the next day isn't a big deal? So glad you cleared that up. I feel stupid now for even thinking anything was wrong," he snapped bitterly. It was out of character for him to be so sharp with her, he knew, but his sleep schedule, quality and quantity were all so screwed up he felt justified to be a little more ill-tempered than usual.

"The sarcasm," she lightly chided him before continuing. "And that's not what I meant," the lady replied with patience that only a mother could have. "I'm saying children are different from adults. They don't understand how to express themselves as well nor do they have the same difficulties as adults do. They see the world in a different way. The problem could be something you're not considering."

"Then could you please enlighten me? I've tried all I can think of and nothing is working," Sans sighed, sliding down to sit in front of the door.

"Unfortunately, I don't have the answer. No one may have it and it may just be a phase they're going through," she suggested. As patronizing as "a phase" sounded to him to explain Frisk's behavior, he wished to god that's all it was despite how unlikely it seemed. "Just think about this. There's a time and place with children to be strict and then another to give them comfort. Even one such as that child needs guidance and support sometimes."

"I'm not really the wise old man type if you haven't noticed," Sans pointed out dryly. "I honestly don't have a lot to give the kid."

She chuckled. "That may be, but you are trying. And if you try, the child will see that. The way they see things is… quite remarkable. Together, I'm positive you two will be able to find the solution."

Sans looked up above as if the answer could be revealed to him in the clouds. Yet he was just given a sky (or ceiling) of solid grey as unyielding and dismal as his predicament.

"I don't want to mess this up," Sans admitted so quietly he wasn't sure if the lady would hear him or if he even wanted her to hear his deep confession. He'd only ever had to worry about his and his brother's survival. If they were alive and strong then all was right with the world. But Frisk's problem lay outside of the realm of his knowledge and experience. It lay in a place he'd never been in or understood and all he truly knew what to do was watch.

It was the same thing he'd always done. Most other things he'd given up on and been just fine with leaving them behind. But Frisk was one thing, the one person he couldn't do that to. But if he made a move, if he made the wrong step, then what if it all fell apart? What would it do to Frisk? This seemingly fragile problem was mental, biological or something, but the point was that he couldn't just beat it up and walk away with it all solved. And at the end of the day, that's all he really knew how to face anything.

He was new to taking care of something. Every day with Frisk was entirely a learning experience for him. He wasn't a perfectionist or disillusioned. He could make mistakes in some places and not forever screw the kid up, but this didn't seem like a place where he could make a single one. The way you grew up, the way you were raised could do irrevocable damage. He understood that all too well. Things might have been different in the human world, but down here there was nothing that could help Frisk and ensure that the next day the kid would be alright.

"I understand," she told him softly in a tone he rarely heard from her. "But all we can do is live and learn. There's no such thing as going back in time to fix our mistakes, but that shouldn't scare you from acting. It should motivate you even more to make sure you fix them after they're done."

"Right… " Sans said in a daze. After a pregnant pause, he added, "Good talk. I gotta go." Without waiting for her response, he pulled his hood over his head and pushed off of the door, his eyes fixed on the ground thoughtfully.

He didn't expect a revelation or some secret wisdom to be bestowed upon him from talking with the woman, but he'd hoped for something more than "if you screw up, you screw up, so just deal with it and move on." To be fair, she'd said it more eloquently, but that was the gist of what Sans had gotten and he somehow felt even more forlorn now than when he left.

As he walked away to head back home, he failed to notice that there was a very small break in the foreboding grey clouds.

…

"No baking today, huh?" Sans asked Frisk casually as they walked despite having observed so himself when he'd seen that Undyne's house was still standing.

The child shook their head with a certain amount of relief.

He'd decided to stop by Undyne's house on his way home to see whether it was up in flames or not. If it was, then he'd know to look for his brother and Frisk at their home or Alphys' place since those were the only two places they went after Undyne's house burned to the ground. He'd be hard pressed to admit it, but he also wanted to check on Frisk. He could only imagine them passing out again, but worse, like into a drawer of knives or something despite his confidence in Undyne.

When he'd arrived Undyne and Papyrus had been in the middle of some heated cooking debate over the best way to make meatballs or something. Meanwhile, Frisk was safely sitting at the table, fed and drinking some tea (probably for their throat) while watching some anime Undyne had borrowed from Alphys. His brother and the royal guard had immediately turned to Sans to be the judge, but the lazy skeleton had just shrugged.

"I don't know any butter than you two do. It'd be im-pasta-ble for me to say."

He'd gotten twin scowls at that before being deemed by Papyrus as an unfit judge. Undyne had immediately suggested asking Alphys instead, to no one's surprise, but regardless of the possibility of Alphys being biased, Papyrus would never give up the chance to be proved right.

And that was how he ended up getting saddled with taking Frisk home. He didn't mind though. He'd gladly keep Frisk away from the nearly mad scientist who always had some experiment she were eager to impart on a less than willing participant. With Frisk's mellow, compliant demeanor, for all Sans knew he would end up getting the kid back with functioning animal ears and an extra appendage. And that would be if he was lucky.

Sans blinked when he heard something fall behind him and glanced back to find Frisk hadn't been matching his pace for at least twenty feet as they were currently lying face down in a snow poff with no annoying dogs to cushion their landing. It would appear at first that the kid had tripped from the depth of the snow judging from the way that their legs sunk into it almost up their knees, far surpassing their boot line. However, as they pushed themselves up, face covered in the frozen fluff, they let out a yawn and rubbed their eyes, hardly reacting to their fall just like when Sans had made them spill salt all over their fries. Even as he waited, they struggled to stand, their hands disappearing into the snow every attempt them made to push themselves up, causing them to sink and fall face first into the frosty fluff every time.

"If I didn't give a damn…" Sans muttered, rubbing the back of his skull as he backtracked to retrieve the fallen human. The snow easily melted on their skin and they let out a shiver as the wind blew directly on their damp face. Standing before the child, Sans leaned down to pick them up from under their arms.

"What am I gonna do with you, kid?" Frisk gave a huff of embarrassed defeat as Sans set them down. He really hoped it was the sleep deprivation that was making them unusually helpless as of late.

Once the human was stable on their feet, Sans dusted off the snow from them as best as he could, noting their red face and the dark bags under their eyes with a frown. He pulled off his jacket and slung it over Frisk's shoulders, making sure the hood was securely on their head to combat the chilly wind.

He then turned his back to them and crouched down. "Climb on, kid. At this rate it'll take us forever to get home."

Thankful as they could feel their socks soaked inside of their boots, Frisk hopped onto Sans' back a little too eagerly, endeavoring not to fall into the snow again. Unfortunately, their sudden jump was too much as Sans grunted when he wasn't able to withstand the sudden weight or balance them in time. Sans cried out as he was the one to stumble and fall forward this time. Frisk, having tried to clutch onto Sans by his shoulders, followed his fate and slammed their forehead into the back of his skull with a loud smack. The force of the collision was like a rubber band snapping together as Frisk's head was drawn back by air resistance while their hands on Sans' shoulders tried to keep them close to the monster. Their heads crushing into one another had been inevitable the moment Frisk had leapt up.

This left the two lying on the ground, San on his front while Frisk rolled off onto their back, groaning simultaneously and holding their respective injuries in pain. "I. Said. Climb," was all Sans ground out, rubbing the back of his head.

Once they both recovered, Sans did finally get Frisk onto his back, but the causalities of Frisk's carelessness showed as Frisk's HP had fallen to 15 while Sans' was left at 0.99. The teary-eyed child sniffled and held a snowball to the bruising spot on their forehead while using their other arm to grasp Sans' neck. At least Sans' jacket was keeping the wind and cold at bay. (2)

"Kid…" Sans murmured in a low, scolding tone causing Frisk to nod timidly in acknowledgement as they walked, spotting Snowdin ahead. The skeleton sighed in defeat. "Let's go get you a cinnamon bunny."

…

It started far earlier than Sans had expected. They'd all went to bed, Frisk with the blanket he'd given them, camping out at the foot of his door which he once again left wide open. It was a bit of a challenge as it was too easy for him to drift off at his station on a flat wooden surface let alone his own bed, but he stayed awake, occasionally glancing over at Frisk since his vision had already adjusted to the darkness. They slept soundly, their little body rising and falling with even breaths. He'd expected that he'd have to wait for hours on end for the kid to wake up if they did so at all considering he hadn't noticed them sleeping out there the other night.

But within two hours he could hear the whimpering and the sudden shifts they made under the blanket. This made him frown. If this was a typical night for them and the kid woke up from this nightmare-like fit in the same amount of time that they had last night, then they must have been standing beside Sans' bed for at least an hour or more waiting for him to wake up since he was never roused earlier than one in the morning.

The situation was oddly comforting and distressing simultaneously. There was a sense of control in predictability, but what he was predicting was Frisk being inexplicably tormented. In essence, he somewhat knew what to expect after it had been happening for so long, but he still didn't know what to do about it. But he wasn't about to ignore it either.

The gentle touch he wasn't used to employing took effort, but very carefully he used his magic to grasp Frisk's soul and lifted them from the floor. Thankfully, it didn't cause the hell-raising reaction he'd gotten before when he'd tried to wake them up and he gingerly levitated Frisk over to the bed, moving over to make room for the kid. Curled up in a shaky little ball on the mattress, Frisk was in the same state as the previous night, eyes open, tears running down their face and that deep-seated panic caused by some unknown terror present as they twitched and jerked timidly, mumbling nonsense.

"Damn it, kid," Sans murmured with a disheartened scowl. Watching this was like having a knife twisted in his non-existent heart. "What am I gonna do with you?" The question he'd puzzled over again and again, so much so that it was starting to sound hollow and lose its meaning.

The only time that Frisk didn't do this was when they had crept into bed with him the other night. At least, Sans thought so. He'd been so fatigued and worn out at the time. Could he have really slept through Frisk doing this right beside him?

Obviously trying to pull them from sleep wouldn't be an ideal situation if they started screaming bloody murder again, but maybe he didn't have to. It was against all he knew and understood, but maybe fighting it wasn't the right thing to do. Maybe going with it was the right answer. If there was really a "right" or "wrong" fix to this anymore. And maybe tomorrow his brother would start dating Mettaton, the TV star, Undyne would bake without sending her house up in flames and Sans would start drinking ketchup instead of mustard.

"Just… try…" he whispered to himself. He'd never liked fear getting the best of him. It was a weakness and he hated being seen as weak. But for once he had something much more important he might lose than his pride if he succumbed to it.

Sans gradually laid a hand on Frisk's head, anticipating a freak-out the moment Frisk registered the touch. However, nothing happened. Good _or_ bad. Frisk still trembled under his hand and their breaths were unsteady and sharp like their air way was partially blocked and they had to make up for the lack of oxygen through forcing more in at once with each inhale.

As if he were defusing a bomb, Sans was sweating while trying to think of what to do next when the kid didn't reject the contact. That was when something tugged on his shorts abruptly, making him jump before he spotted the small hand clutching his clothes. Then he saw it. In his deep thought he hadn't realized that Frisk's shaking wasn't the only thing causing their head to move. It was very subtle, but the kid was nudging his hand with their head, their body inching closer as their head moved forward and back occasionally.

Sans was not considered the most perceptive guy when it came to reading other people. To really get a point across to him typically took a blunt comment to his face which he would or wouldn't choose to ignore. But his time with Frisk had taught him to read into the tiniest actions. A curled lip, the shift of one's gaze to the side, the firm set of one's jaw, hands clenching thoughtlessly and even the smallest glimmer in the eye. All of these things spoke volumes when they used to mean jack shit to him if he even noticed them. And while he couldn't say he was suddenly an expert at reading people, he'd become very attuned to Frisk and how they conveyed so much with so little.

That was how Sans ended up running his hand down Frisk's head, stroking it softly before he'd even made a conscious effort to do so. They were unconscious and afraid, but they were still Frisk. A pat or a stroke meant so much more to them than the idle gesture might have intended. They weren't used to touching or being touched. Sans had gathered that much. But any non-threatening contact, they welcomed like water in a desert. It was a novelty to them and because of that, every single moment of it, whether they shyly grasped someone's hand or received an overly enthusiastic hug, was nothing short of magic to them.

At first nothing happened, but Sans kept at it, until Frisk's shaking stopped and they paused. Very gradually, the kid lost that wide-eyed terror which dissolved into confused alert. They were utterly still, as if still trying to assess the situation. By now they'd found their way into Sans' lap allowing him to feel their body relaxing on top of him. Their eyes still darted about, unsure and watchful of something not in the realm of reality.

"Kid, it's me," he spoke softly, slowly coming to find his rhythm with petting Frisk's head as they responded well in turn. "Everything's okay. Nothin's gonna hurt ya." What he would have given to hear those words from someone else long ago. At least he was here to tell them to Frisk and mean it, even if they couldn't really hear or understand him.

It was probably because of this that he was prompted to go on. "I know you've had it rough. Ever since you got down here you've been given a lot of shit." And possibly been killed more times than he would ever know. "Most kids would cry and give up, but not you. You're determined and stronger than a lot of monsters down here. No matter what they did… or what _we_ did, you held on." He couldn't escape the responsibility.

Even if no one ever accused him of it, Sans knew that he'd contributed to Frisk going through hell on their own when they'd arrived. He hadn't known Frisk then, but what kind of sick fuck watched an innocent child struggle in a world they didn't understand? He might have never done a bit of damage to Frisk himself, but he was guilty all the same. He'd watched and even laughed when at times when they'd gotten hurt by refusing to fight.

"You're strong enough to beat this too. I know it. You never hurt anyone or took the easy way out. You didn't break under the pressure and fight back." Even when everyone wanted them to. "You still cared about monsters that wanted you dead when anyone else would've said to hell with it and all of us." Frisk was a soul too gentle and good for this world. But it didn't make them weak like he'd first thought. "You refused to hurt anyone even when they deserved it." And expected nothing in return.

"You never gained LOVE, but you gained love." Sans chuckled wryly at the irony. This was the same kind of speech he would have scoffed at before grinning while he blasted the giver of it to dust not long ago. "Does that make sense? Maybe not." He admitted to the unconscious child. "I… what I'm trying to say is… I love ya, kid. And I'll help you through this no matter what. I can't make this stop, but I'll never give up on you." How could he when Frisk had done the same for him unconditionally?

The grip they had on his shorts loosened and their silent crying ceased now that it had lightly wetted his shorts. Their breathing grew more even as well, only the remnants of a shaky breath occurring now and then. Light sweat coated their forehead and clung to Frisk's hair as they calmed, blinking once and then again with that glassy, dull look in their eyes.

It wasn't quite so simple as stroking their head as the slightest shift from Sans underneath them caused them to tense. Their limbs still trembled slightly and incoherent mumbles still left their mouth as their frame shook. But rather than being a minute away from a panic attack, Frisk appeared simply restless and weary.

Then they stilled, relaxing completely and Sans wondered if he'd finally done it. He watched them for a minute more and would have held his breath if he had any.

Suddenly, their eyes squeezed shut with a soft whine then snapped open and blinked before they began to pant heavily. Their gaze darted left and right, baffled, but with a comprehension they didn't have before. Sans saw the moment that it dawned on them that they were in his bed. Then, when they looked up and met his eyes, they quickly shot up, crawling backwards and giving Sans a disconcerted, apologetic look. They must have thought they sleep walked into the room or something. It wouldn't have been the most bizarre thing they'd done.

Just as they were about to slipped off the bed to retreat, Sans lifted them with a flick of his glowing hand, it and his eye lighting up the dark room with a red tint. Their feet didn't even touch the ground before Sans had gotten a hold of them and set them back down on the mattress.

"Nu-uh, kid. No more of that. You're staying here tonight." He tone left no room for argument.

Frisk was stunned and shook their head, hiccupping from the after effects of their sobbing. They sat on their knees, wiping at their face furiously, likely bewildered as to why they were so emotionally charged despite just waking up.

Sans sighed. "Frisk. I'm not mad you," he said, trying to make his burning eye as unintimidating as possible. "I brought you in here myself," he told them. In response they paused in trying to dry off their face and sniffled, looking much like a cornered animal; scared and uncertain of how to react.

Sans mustered his patience and trained his expression to be as neutral as possible since the kid looked like they might break down if he blinked the wrong way. Inspiration struck then and he glanced around until he spotted it. Sticking his hand out, he levitated his jacket off the floor and then pulled it over to the bed with a flick of his finger. The red glow around it was lost as Sans let gravity take over and he caught it easily with one hand. He then held the jacket at arm's length for the child to take like a peace offering. They regarded it cautiously before curling their fingers around the black article to take it.

With a small but quick tug, Sans dragged them forward and cupped his other hand over the back of their head as he laid them both down on the bed, fighting off falling asleep right then and there. They were always strangely fond of his jacket and, as he'd suspected, it seemed to soothe Frisk to calm down somehow. They didn't pull back when Sans dragged them both to lay down and instead let out a tiny, shuddering pacified sigh after a moment. Seeing this and trusting Frisk not to bolt the moment he moved, Sans pulled the jacket out from between them. He then laid it over Frisk, momentarily removing his hand on their soft tuft of hair only to place the hood there before replacing his hand on the back of their head.

"It's okay, kid. I'm right here," Sans reassured Frisk, pulling them to his chest. "You're not alone anymore." And Sans suspected they had been for far too long, before they'd even climbed Mt. Ebott.

Frisk's red eyes widened, softening before squeezing shut with a quiet hiccup. Fresh tears spilled from their eyes as they nuzzled into Sans, grasping his shirt in their little hands and sobbing softly. However, unlike the night before, Frisk wasn't hysterical or emotionally wound up like they might explode. Their crying was subdued but relieved like a weight had been lifted and they were no longer suffering under the burden of it.

He didn't know how long it took, but after a while Frisk's weeping quieted and they stilled atop of stomach, their body once again rising and falling evenly.

"Sweet dreams, kid." With that, Sans shut his eyes and slumbered soundly, clutching the human child to shield them from any invisible terror.

…

"I'm headin' to bed early," Sans announced with a yawn the following night. Papyrus was cleaning his attacks and Frisk was coloring on the floor as he drudged up the stairs, pausing at the top.

"Oh. I almost forgot," he murmured with a neutral frown. Frisk was lifted into the air suddenly by their soul causing them throw their limbs out unsteadily in surprise while Papyrus watched on curiously.

"Night, bro," Sans said without another word, continuing towards his room.

"Wait! Sans! What do you need the human for?" Papyrus asked, pointing his bone at his brother quizzically.

"Why? Are you using them right now?" Sans asked nonchalantly.

"Well, no, but-"

"Then it's all good. I'll give em' back in the morning," he promised Papyrus. "Can't have them miss breakfast. It's the second most important meal of the day. Right after brunch, but right before linner," Sans mused.

"Best that you do! I, the Great Papyrus, have plans for a hearty, nutritious meal as always," he replied approvingly.

"That's real cool, bro. See you in the morning," Sans left, still dragging a stunned Frisk along with him in the air. When they arrived at his door, Sans set them down and turned to walk in, stopping only when he noticed Frisk wasn't following and gave a glance back.

At Frisk's lost look, the upper part of Sans' eye socket rose in his impression of raising a brow as he replied bluntly. "I'm going to bed. You're coming with me, kid. Thought that was obvious."

Still perplexed, Frisk pointed to the blanket and pillow on the couch downstairs that they wanted to retrieve, but Sans just shook his head, giving them an odd look.

"My bed has plenty of pillows and covers. What? Do you get that cold?" he asked them.

The kid was making him almost feel guilty for thinking that he'd make them sleep on the floor again, especially when he'd felt fairly confident they'd had a breakthrough this morning.

Just like before, the kid's memory of it all was hazy at best and they hadn't even fully remembered waking up and trying to retreat back to the front of his door. At best, they'd thought it was a dream.

As they'd sat in bed that morning, Sans, reading the solemn, unspoken question on their face, had nodded. "Yeah, it happened again." Frisk's dour expression had prompted him to quickly add. "But you didn't practically wake up the whole Underground this time." Frisk's head perked and they'd looked at him hopefully. "I'm serious. You were doing it for a while, but calmed right down."

The skeleton wasn't sure if it was the extra sleep they got or the encouragement that they might be getting better, but Frisk had been quite animated and particularly cheerful the entire day, making both Sans and Papyrus just as happy and relieved.

Standing in front of his room with Frisk, Sans gave them a look as if they were wasting his time. "So are you coming or do I have to drag you in kicking and screaming?" Sans questioned Frisk with a smug grin of amusement. Frisk didn't look impressed and pouted, but strode into the room nonetheless.

"I know, I know. You're not howling with laughter because you find this to be a wail of a problem and you probably want to start tear-ing your hair out, but don't worry. If you need time to shriek a way to look at the humerus side of the all this, I'll gladly sob whatever I'm doing to yelp you."

Frisk just stared at the comic before slamming the door in Sans' face.

"SANS! I'M PUTTING KETCHUP IN YOUR BREAKFAST!" Papyrus roared irritably from the first floor.

"I'm still gonna relish this moment." Sans shrugged.

"SAAAAAANS!"

…

It was a beautiful day outside. Birds were singing and flowers, despite the snow, on the unusually warm day in Snowdin were blooming. On days like these, kids like Frisk… needed a lot of sleep.

The sun coming in through the window warmed the bed perfectly as Sans laid back and enjoyed the quiet morning, for once not lulled to sleep by the weather. Frisk was out like a light and it really wouldn't have surprised Sans if the kid slept the entire day. He'd woken, but felt surprisingly rested, yet he hadn't felt the urge to go back to sleep or get up. Plus, the latter involved possibly waking Frisk, so he was content to just lay there and let himself drift, not sleeping, but not really thinking much either. He was just relishing the quiet, the calm, bright day and the peacefulness of the child lying beside him with his hands behind his head as he stared at the ceiling.

His vague reverie was cut short when he heard a soft moan followed by a satisfied sigh and he glanced over to see Frisk snuggled in his jacket and rubbing the sleep from their eyes. He hadn't been quite as confident that Frisk would sleep through the night as he'd seemed, so he'd given it to the kid to sleep with, claiming that it should keep them warm enough for the night. The hoodie hadn't failed him so far.

"Sleep well?" When Frisk nodded with a drowsy, contented smile, Sans couldn't help grinning back. "Glad to hear it, kid." Frisk's smile waned then and they looked to Sans apprehensively, the question clear on their face.

"Nope," he supplied off-handedly. "You didn't wake up a single time."

The look on their face was so completely elated. They began to tear up and sniffled lightly.

"Hey, don't start the waterworks now, kid," Sans teased them lightly, growing sober. "We should see how the week goes before we start breaking out the hot mustard."

The child nodded in agreement, but was overjoyed nonetheless and dried their eyes on his sleeve before exhaling. Just then they abruptly sat up, seemingly deep in thought before fixing their stare on Sans. Curiosity filled the monster as they then gestured for Sans to come closer looking very intent like they had something to tell him.

"Hm, what is it, kid?" Was Frisk going to grace him with the sound of their voice for once? Humoring them, Sans leaned down until their heads were side by side and listened carefully to what they had to say.

"I love you too, Sans."

Warm lips pressing against his cheek startled the skeleton, causing him to instinctively jerk back. His bones rattled as he slammed against the wall and stared at Frisk like they'd just grown another head, gaping in shock with a deep blush coloring his face. The child's response was a cherubic yet sly smile as they cuddled inside of Sans' jacket.

"What… am I gonna do… with you… kid?" he asked with a mortified groan, burying his face into his hands as Frisk let out a soft, bubbly giggle.

"Still…" he added quietly, sliding his hands over his mouth bashfully as he spoke. His soft utterings caught Frisk's attention and they paused with a gasp. Curving their hand, which was covered by the oversized sleeve of his jacket, around their ear, Frisk signaled for him to speak again.

"Tough luck, kid, I'm not gonna say it again," he said smugly despite his blush. Sans stuck his tongue out at the human as they sulked, their lip jutting out in discontent. "Now go downstairs and bug Papyrus about breakfast. I need to change."

Huffing, Frisk scratched the back of their head with a yawn and climbed out of bed.

"And give me back my jacket."

With a scowl, the human reluctantly handed it over. It occurred to him that they might be getting _too_ attached to it. It was still _his_ , after all.

Sans then stood, stretching and bending his stiff bones as Frisk walked out. "And don't let him put ketchup in my food!" he added.

Returning his stubbornness in kind by sticking their tongue out at Sans, Frisk exited the room with no such promise.

"I think I'll skip breakfast," Sans deadpanned, rejecting his soon-to-be tainted food as he threw on a new shirt and pulled on his wrinkly black, hooded jacket.

"God… what the hell does that kid do to me?" Sans grumbled bashfully to himself once he was alone and dressed before he headed downstairs to meet his brother and Frisk.

 _"Still… I don't know what I'd do without you either, kid."_

* * *

Acknowledgements:

(1) Name of Sans' pet rock, Lump, comes from ArumAnimus' fanfiction Aftertale (not the AU). That's right. I'm giving credit for a rock.

(2) Scene inspired by comic by Nyublackneko. Link in my profile.

(3) Story Art: Link(s) in my profile

Author's Note: I hope you enjoyed my first oneshot! If you couldn't tell from the title, this story is based off of night terrors. To anyone who doesn't know, night terrors are different than nightmares, explaining some of Frisk's behavior. Here are some excerpts from the internet to sum them up and explain some of what went on in the story.

 _"During a night terror, a child might suddenly sit upright in bed and shout out or scream in distress. The child's breathing and heartbeat might be faster, he or she might sweat, thrash around, and act upset and scared. After a few minutes, or sometimes longer, a child simply calms down and returns to sleep."_

 _"Unlike nightmares, which kids often remember, kids won't have any memory of a night terror the next day because they were in deep sleep when it happened — and there are no mental images to recall."_

 _"If a child is unresponsive during night terrors, parents should not try to wake the child, but hold the child firmly and speak soothingly until the episode ends. Usually, the child will ease back to sleep afterwards."_

 _"Night terrors have been noted in kids who are:_

 _-overtired or ill,_ _stressed, or fatigued_

 _-taking a new medication_

 _ **-sleeping in a new environment or away from home** "_

This started slightly based off of my own childhood. I didn't have night terrors, but I would wake up, go to my parents' room and when they started locking the door, I just slept outside in front of it. I'd be too afraid they'd get mad if I woke them up and instead scared the hell out of them when they woke up on their own.

In light of this, I'm sorry if my portrayal of night terrors isn't accurate. I did some mild research and tried to match it as well as I could, but keep in mind this is just a piece of fiction that came to me one day. I got excited and motivated to write it out and nothing more.

I wanted to do something that departs from the usual Undertale stories of Frisk and Sans having nightmares of other timelines/Chara and looking for solace in one another. I'd like to leave this story up to as much interpretation as I can, but these are just some of my personal inspirations while writing it. Also, I enjoy the dynamics of Sans and Frisk's relationship in both Undertale and Underfell. In both cases Frisk is an incredibly tough little kid, but they're still just that. A kid. And seeing Sans deal with gives me the feels.

I hope you enjoyed this little early Valentine's Day story. Please let me know what you think. I love feedback. ^_^


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